Making of articles from sheet material



May 21, 1940. w. wALKEl 0F ARTICLES FROM SHEET MATERIAL Filed Aug. 3,1938 MAKING WALKER WnJJ M WEMM QW$MW Patented May 21, 1940 UNITED.STATES MAKING OF ARTICLES FROM SHEET MATERIAL 2 William Walker, London,England, assignor to Celanese Corporation of America, a corporation ofDelaware Application August 3, 1938, Serial No. 222,833 In Great BritainAugust 14, 1937 Claims.

This invention relates to articles made from artificial sheet materialand especially sheet material having a basis of cellulose acetate.

Artificial sheet material is at the present time finding an increasingnumber of applications.

'Sometimes, however, particularly when the material is subjected torepeated flexing, the edges of the material are broken with the resultthat the strength of the whole sheet is seriously impaired so that thesheet easily tears or breaks right across.

' According to the present invention articles made from artificial sheetmaterial are formed with portions reinforced by textile fabricimpregnated with the substance of the sheet material. This result isobtained with the aid of what is hereinafter in the description andclaims referred to as a protective coating, the sheet material beingformed by depositing a film-forming solution on a casting bed, thesurface of which is formed partly of this protective coating and partlyof a textile fabric to which the artificial sheet material stronglyadheres. In practice the method employed may comprise first ap- 05plying the protective coating to a fabric base of at least the area ofthe article to be made, the protective coating being provided on thegreater part of the surface of the fabric base leaving uncoated onlythose portions, e. g. the edges, where it is desired to reinforce theartificial sheet material, then forming the artificial sheet materialupon the whole surface of the fabric and stripping from the assembly theportion or portions of the fabric provided with the protective coating.

The protective coating employed is one to which the composition formingthe artificial sheet material does not strongly adhere. Waxes andgelatine are of general application in this connection but withartificial sheet material having a basis of cellulose acetate it hasbeen found most advantageous to use a protective coating of ethylcellulose. The appearance of the artificial sheet material can be variedsomewhat according to the thickness of the protective coating applied tothe fabric base; for instance, with only a thin protective coating theartificial sheet material will to a certain extent be given theappearance of the fabric upon one side while with a thicker protectivecoating the artificial sheet material will be smooth on both sides.

An important application of the invention is the manufacture oftransparent sun-blinds such as may be employed outside shop windows tosign protect articles displayed in the shop from the effect of strongsun-light. In producing such a" sun-blind a sheet of strongfabric, e.g.canvas, of the size and shape of the sun-blind which is to beproduced, or slightly larger to provide for subsequent trimming, isemployed as base. The; centre of this sheet of fabric is coated with asolu- 5 tion of ethyl cellulose, a margin being left uncoated at eachedge of the sheet. For instance, in producing a sun-blind 6 ft. squarethearea provided with the protective coating may be some 5 ft. to 5 ft.6 ins. square so as to leave a margin of 36 ins. uncoated; when a largerblind is to be made the margin may be wider and strips running acrossthe fabric may be left uncoated so as to produce a base having two ormore panels carrying the protective coating.

Upon the whole surface of the fabric thus prepared a film-formingsolution, e. g.,, a solution of cellulose acetate, is spread to form asheet by evaporation of volatile solvent from the solution. Preferablythere is employed a solution which flows freely so that a smooth uniformlayer is formed with little or no use of spreading devices. It issometimes preferable, particularly when a large sheet is to be produced,to spray the filmforming solution on to the base to form a film byevaporation of volatile solvent from the solution and to repeat theoperation until a sheet of the desired thickness has been built up. Thefilm-forming solution is, of course, coloured, e. g., yellow, orange orgreen, in view of the intended use as a sun-blind of the article to beproduced.

After the sheet'of cellulose acetate has hardened upon the fabric basethe centre portion or portions of the fabric, i. e. the portion orportions originally provided with the protective coating, are strippedfrom the assembly to leave a transparent sheet of cellulose acetatesupported by reinforcing strips of fabric impregnated with celluloseacetate. In this connection it is to be noted that before theapplication of the cellulose acetate coating, and if desired before theapplication of the protective coating, the bounderies of the portion orportions of the fabric to be removed subsequently may be, and preferablyare, weakened, e. g., by perforation.

The production of a sun-blind in the manner described above isillustrated in the accompanying drawing in which Fig. 1 shows aperspective view of the sunblind during the course of its production;

Fig. 2 shows a section of the same; and

Fig. 3 an enlarged view of a portion of the canvas reinforcing fabricemployed; while Fig. 4 shows a. modified form of sun-blind.

Figs. 1 and 2 of the drawing show the centre portion l of a canvasreinforcing fabric with its adherent layer 2 of protective coating beingstripped from the layer 3 of a composition having a basis of celluloseacetate, leaving a reinforcing strip l of canvas impregnated with thesubstance of and strongly adhering to the sheet fore the application ofthe protective coating by a succession of cuts 5 (see Fig. 3),successive cuts being separated slightly at the peaks 6 of theserrations formed by the cuts, so that the centre portion I of thecanvas adheres to the reinforcing strip 4 until it is torn therefromafter formation of the sheet of cellulose acetate com position on thecanvas.

In the sun-blind shown in Fig. 4 the reinforcing strip 4, besidessurrounding the sheet of cellulose acetate composition 3, also forms twostrips across the width of this sheet, thus dividing it into threepanels.

' Having described my invention, what I desire to secure by LettersPatent is:

1. Method of producing an article composed of artificial sheet materialand having portions of its area reinforced by a textile fabric, whichcomprises first applying a protective coating to a textile fabric of atleast the area of the article to be made, the protective coating beingprovided on the greater part of the surface of the textile fabric,leaving uncoated only those portions where it is desired to reinforcethe artificial sheet material, then depositing a coating of artificialsheet material of uniform thickness upon the whole surface of thefabricand stripping from the assembly the portion or portions of thefabric provided with the protective coating.

2. Method of producing an article composed of cellulose acetate sheetmaterial and having portions of its area reinforced by a textile fabric,which comprises first applying a protective coating to a textile fabricof at least the area of the article to be made, the protective coatingbeing provided on the greater part of the surface of the textile fabric,leaving uncoated only those portions where it is desired to reinforcethe cellulose acetate sheet material, then depositing a coating ofcellulose acetate sheet material of uniform thickness upon the wholesurface of the fabric and stripping from the assembly theportion orportions of the fabric provided with the protective coating.

3. Method of producing an article composed of cellulose acetate sheetmaterial and having portions of its area reinforced by a textile fabric,

which comprises first applying a coating of ethyl cellulose to a textilefabric of at least the area of the article to be made, the coating ofethyl cellulose being provided on the greater part of the surface of thetextile fabric, leaving uncoated only those portions where it is desiredto reinforce the cellulose acetate sheet material, then depositing acoating of cellulose acetate sheet material of uniform thickness uponthe whole surface of the fabric and stripping from the assembly theportion or portions of the fabric provided with the coating of ethylcellulose.

4. Method of producing an article composed of cellulose acetate sheetmaterial and having a portion of its area reinforced by a textilefabric, which comprises first applying a coating of ethyl cellulose to atextile fabric of at least the area of the article to be made, thecoating of ethyl cellulose being provided on the greater part of thesurface of the textile fabric, leaving uncoated only those portionswhere it is desired to reinforce the cellulose acetate sheet material,the textile fabric being perforated at the junction of the coated anduncoated portions, then depositing a coating of cellulose acetate sheetmaterial of uniform thickness upon the whole surface of the fabric andstripping from the assembly the portion or portions of the fabricprovided with the coating of ethyl cellulose.

5. Method of producing a sun-blind composed of cellulose acetate sheetmaterial and having portions of its area reinforced by canvas, whichcomprises first applying a coating of ethyl cellulose to a piece ofcanvas of at least the area of the article to be made, the coating ofethyl cellulose being provided on the greater part of the surface of thecanvas, leaving uncoated only those portions where it is desired toreinforce the cellulose acetate sheet material, then depositing acoating of cellulose acetate sheet material of uniform thickness uponthe whole surface of the canvas and stripping from the assembly theportion or portions of the canvas provided with the protective coating.

WILL' IAM WALKER.

